Pythagoras cup. The potter Vagelis, Kokkari

It is said that Pythagoras invented the cup to learn his students not to fill the cups to the edge and to be moderate when drinking wine.

When the Cup is filled then the outer tube in the center of the Cup is also filled through small holes in the bottom. If the level of the liquid in the cup exeeded the height of the inner tube the cup was immediately emptied through the hole in the bottom.